Technical Abstract:
Zebra chip (ZC), a new and economically important disease of potato (Solanum tuberosum L.), has been documented to occur in commercial potato fields in the United States, Mexico, Central America, and New Zealand. This disease has caused millions of dollars in losses to the potato industry. Whole crops might be rejected because of ZC, often leading to abandonment of entire fields. Plant growth and yield are severely affected by the disease. Additionally, chips or fries processed from ZC-infected tubers exhibit dark stripes that become markedly more visible with frying, and hence are commercially unacceptable. The disease causes serious losses to the fresh market, tablestock and export potato industry as well. ZC-infected tubers usually do not sprout and if they do, produce hair sprouts or weak plants. Finally, there are indications that ZC symptoms might develop in tubers during storage. ZC has been associated with a previously undescribed species of liberibacter, tentatively named “Candidatus Liberibacter solanacearum”, also known as “Ca. L. psyllaurous”. The bacterium is transmitted to potato by the potato psyllid, Bactericera cockerelli (Šulc). All commercial potato cultivars appear to be susceptible to ZC, and management tactics targeted against the potato psyllid are the only means to effectively manage the disease. Furthermore, there are concerns about quarantine and trade issues in psyllid-affected regions because some countries now require that shipments of potatoes from certain growing regions be tested for the disease before the shipments are allowed entry. ZC history, geographic distribution, biology, epidemiology, and management are discussed herein.